Roads lead to peril for the Amazon

US researchers, modelling the effects of development in Brazil, say nearly half of the Amazon forest will be totally deforested or heavily degraded in 20 years.

The study, by researchers at the National Institute for Amazonian Research in Brazil and the Michigan State and Oregon State Universities in the US, is published in the current issue of Science.

The current level of forest cover now remaining in the Brazilian Amazon.

The study models the effect of a massive infrastructure project funded by the Brazilian Government and international private investors called "Avança Brasil" (Advance Brazil). While the project is designed to promote economic develoment, the researchers caution that environmental losses could offset economic gains.

"Problems with deforestation in the Amazon are not new," say the researchers. "But this study is one of the first to look at the wider range of causes, ranging from population growth to economic policies, pipeline construction, roads, power lines, an influx of multinational timber companies, slash-and-burn farming, ranching, mining, oil exploration, and many other issues."

Non-indigenous populations in the Brazilian Amazon have increased about 10-fold since the 1960s, from two million people to 20 million, the researchers say. Investments totalling $40 billion are planned just in the next seven years under the Advance Brazil economic development program.

"Key environmental agencies in Brazil are largely excluded from the planning of these developments," they say.

The researchers identify roads as one of the key problems.

"Roads that once were more confined to the perimeter of the Amazon Forest are now penetrating the heart of the basin, and the many land uses made possible by these roads are destroying the forests," they say.

The researchers report that the rate of forest destruction is now almost 5 million acres per year and the highest in the world.

Under the less optimistic of two models developed to assess the future impacts of these trends, less than 5 percent of the land will survive as pristine forest, and 42 percent of the region will either be totally deforested or heavily degraded by the year 2020.

The "more optimistic" scenario (above) and "less optimistic" scenario (below) predicting forest degradation by the year 2020. Black represents heavily degraded, including savannas and other non-forested areas. Red is moderately degraded, yellow is lightly degraded and green is pristine.

The more optimistic scenario assumes people will not venture more than about 50 kilometres from the new roadways, however the researchers say that in the past 20 years, additional roads have led to development more than 160 kilometres deep into the forest.

"Part of what's important about this report is we tried to tie together a lot of different components that often are not considered, but have long term impacts on land use," said researcher Scott Bergen, a specialist in geographic information systems, remote sensing and spatial ecology from Oregon State University. "The ultimate conclusion is that despite the best efforts of many people and hundreds of millions of dollars being spent on conservation, the rate of deforestation in the Brazilian Amazon has not decreased and in some places in still increasing".

Co-researcher Mark Cochrane of Michigan State University who helped create the study's satellite-based models said his team is not blind to Brazil's need for economic development, but that it's imperative the country knows where the roads will take them.